Changeable vault structure for electric melting-furnaces.



B. C. KVERNO. CHANGEABLE VAULT STRUCTURE FOR ELECTRIC MELTING FURNACES.

APPLICATION FILED NOV. I0, I9I6.

Patented Feb. 20, 1917.

I Inventur:

B- E Kv-Ern Attcmney f i CHBIBTIAN KVEBN, 0F HAUGESUND, NORWAY.

CHANGEAIBLE VAULT STRUCTURE FOB ELECTBGMELTING-FUBNACES.

Specication of Letters Patent. I

Patented Feb. 20, 1917.

Application med November 10, 1916. Serial No. 180,560.

To all whom it may concern Be it known that I, BERNHARD CHRISTIAN KvaanN, citizen of Norway, residing at Haugesund, Norway, have invented new and useful Improvements in Changeable Vault Structures for Electric Melting-Furnaces, of which the following is a specification.

The present invention relates to arrangements in vaults and vault structures for electric melting furnaces, whereby certain inconveniences existing in the constructions hitherto known are avoided.

It is a well-known fact, that the vault-- structure in completely or partly closed electric melting furnaces is less durable than the other parts of the furnace except the electrodes. rl`he vault structure therefore must be renewed from time to time. In order to be able to do this it has been necessary hitherto to place the'furnace out of operation and to letit cool completely. To obtain a safe and continuous operation it therefore was necessary to have more furnaces standing in reserve, and as a consequence thereof ,the costs of construction and operation were high.

Another inconvenience in the vault-structures hitherto used is that the apertures which must be arranged in the same in order to control the work of the furnace and to treat the materials by tools have necessarily been made rather large in order to enable picking-down into the charge through these apertures directly under the latter and to lthe sides. When the shutters or valves, which close the channels conduct ing down to the melting space, are opened, the gas flows out and burns, if there exists an over-pressure within the melting space. The fiame often may be so large that it makes work with tools through the shutter, such as sweeping for instance, impos sible. lt is still more inconvenient, if there exists a pressure less than atmospheric within the furnace, because in such case air flows down through the opened shutter, the consequence being that the gas burns within the furnace and causes so high' an increase of the temperature that the vault structure of the furnace is damaged. Explosions within the furnace-may also take place because of such an inflow of air.

Vault-structures for electric melting-furnaces have been previously made, in which the fire-bricks in the furnace, either each separately or in aggregate are attached to overlying carrying'parts of metal.

According to the present invention the carrying parts consist of beams arranged ,that a coherent structure is formed or being arranged as more complete aggregates,

each of which may be separately lifted up from the furnace. It thereby is possible, without cooling the furnace, to lift off the vault -structure completely or partly in a short time and to replace the same by a new one.

The carrying beams are lying above the fire-bricks and are consequently protected against the direct heat from the melting space. Nevertheless it is preferred, in consideration of an increased durability, to water-cool the beams aswell as the bolts or other members connecting them with the bricks.

Along .the outer edges of the vault-structure ball-valves may be arranged. Each valve consists of a circular hole made in the structure and covered by a ball of a larger diameter than the hole. Through the ball passes a hole. the diameter of which suits for the introduction of a. crowbar for working the materials within the furnace. When the ball is so placed that the hole in the same is horizontal, there is no aperture down into the furnace. If the furnace is to be worked, the crowbar is passed through the ball and the latter is turned so that the crowbar passes down into the furnace. One thereby is able to pass the crowbar down in different directions without having any aperture down to the melting space, because the hole is always covered by the ball. Around the bed of the balls there may be cast at a suitable distance a ring which is lled with sandor fine charging material in order to provide a further tightening around the ball.

` A constructional form of the invention is illustrated in the annexed drawing, in which:

Figure l is a vertical section through the upper portionv of the' furnace, and 1 Fig. 2 is a corresponding plan view.

As shown in the drawing the surrounding -ais built of fire-bricks suspended upon bolts -bpassing down through the carrying beams c-Q Between the surrounding -aand the sides .-41- of the furnace covers -dare resting, these covers having downwardly directed flanges -kprojecting into open channels filled with sand. Such channels are formed intop pieces -gresting upon `the upper edge of the furnace walls and also in lateral extensions '-mw forming portions of the carrying beams -c-. In' holes -fnfmade in the covers are resting balls -eprovided with small penetrating bores for the insertion of crowbars and thereby controlling the operation of the furnace.

ranged, and between this flange and the ball is filled fine charge-material, whereby the ball-arrangement is made gas-tight. The charge-material is introduced into the furnace through the space around the electrodes -A-a. This space between the electrode and the outer cover is normally sealed by a removable cover (not shown).

The most important advantages obtained by the arrangement according to this invention may be summed up as follows:

1. The vault-structure or parts of the same may be easily and rapidly changed without the furnace bein cooled.

2. The durability of the vault-structure is increased thereby that it is cooled by the Around each ball an l upwardly directedring-flange fis ar-l i water-cooled carrying-beams and' the connections between the beams and the firebricks. Y

3. The operation of the furnace may be controlled and the materials within the furnace may be worked by tools without inconveniences such as'those resulting from placing the melting space in connection with the outer air through a large aperture.

Having now described .my invention, what I claim as new and desire to secure by Letters Patent is:

1. In anl electric furnace, independently removable surroundings of refractory mate: rial for respective sections of the entire set of electrodes, removable supporting beams positioned above each surrounding, and means for suspending. each surrounding from the said beams.

2. In an electric furnace having an opening ina part thereof for the introduction of charge-working tools, closing means for the said opening comprising a movable member having a tool-receiving aperture'adapted to` be brought into registration with the said furnace opening. p

3. In an electric furnace having an opening in a part thereof for the introduction of charge-working tools which is provided with a spheroidal socket, closing means for the i said opening comprising a ball fitting rotatably within the said socket and having a tool-receiving aperture adapted to be.

brought into registration with the said furnace opening.

In testimony whereof I have signedmy name to this specification in the presence of two subscribing witnesses.

BERNHARD CHRISTIAN RvaRNo.

.Witnesses SKU LAHN, MAGNUS BUGGE. 

